硬件_LED

LED

---

平台：全志A64

源码：Android 7.1  Linux 3.1

led.c

//没有使用平台总线

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/gpio.h>
#include <linux/cdev.h>

#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm-generic/ioctl.h>


//面向对象封装led信息
struct a64_led{
    //unsigned int major;
    dev_t  devno;
    struct class * cls;
    struct device * dev;
    struct cdev  *cdev;
    int data;
};
struct a64_led *led_dev;


volatile unsigned int *gpco_conf = NULL;
volatile unsigned int *gpco_data = NULL;




int led_open(struct inode *inode, struct file *filp)
{

    //将对应的管脚设置为输出——PL10
    *gpco_conf &= ~(0x07<<8);  //清零    
    *gpco_conf |=   0x01<<8;   //置位
   
    return 0;
}


ssize_t led_write(struct file *filp, const char __user *buf, size_t size, loff_t *flags)
{
    int ret;

    //应用空间数据转换为内核空间数据
    ret = copy_from_user(&led_dev->data,buf,size);
    if(ret != 0){
        printk("copy_from_user error!
");
        return -EFAULT;
    }

    if(led_dev->data){
        *gpco_data |= 0x1<<10; //点灯
    }else{
        *gpco_data &= ~(0x1<<10);//灭灯    
    }

    return size;
}


int led_close(struct inode *inode, struct file *filp)
{
    
    *gpco_data &= ~(0x1<<10);  //灭灯
    
    return 0;
}


static struct file_operations fops = {
    .open = led_open,   // 打开对gpio初始化config
    .write = led_write,
    .release = led_close,
};


static int __init led_init(void)   
{

// 1_实例化设备对象
    //参数1 -- 要申请的空间的大小
    //参数2 -- 申请的空间的标识    
    led_dev = kzalloc(sizeof(struct a64_led),GFP_KERNEL);
    if(IS_ERR(led_dev)){
        printk("kzalloc error!
");
        ret = PTR_ERR(led_dev);
        return -ENOMEM;
    }


// 2_申请设备编号

    //动态申请设备号
    ret = alloc_chrdev_region(&led_dev->devno,10,1,"led_drv");
    if(ret < 0){
        printk("register_chrdev_region error!
");
        ret =  -EINVAL;
        goto err_kfree;
    }

    //申请cdev的空间
    led_dev->cdev = cdev_alloc();
    if(IS_ERR(led_dev->cdev)){        
        printk("led_dev->cdev error!
");
        ret = PTR_ERR(led_dev->cdev);
        goto err_unregister;
    }

    //初始化cdev的成员
    cdev_init(led_dev->cdev,&fops);
    
    //将cdev加入到内核中----链表
    ret = cdev_add(led_dev->cdev,led_dev->devno,1);
    
    
// 3_创建设备文件    
    led_dev->cls = class_create(THIS_MODULE,"led_cls");
    if(IS_ERR(led_dev->cls)){
        printk("class_create error!
");
        ret = PTR_ERR(led_dev->cls);
        goto err_cdev_del;
    }    
    led_dev->dev = device_create(led_dev->cls,NULL,led_dev->devno,NULL,"led");
    if(IS_ERR(led_dev->dev)){
        printk("device_create error!
");
        ret = PTR_ERR(led_dev->dev);
        goto err_class;
    }    

// 4_硬件初始化----地址映射

    gpco_conf = ioremap(0x1F02C04,8);
    gpco_data = ioremap(0x1F02C10,8);    

    return 0;

err_class:
    class_destroy(led_dev->cls);
    
err_cdev_del:
    cdev_del(led_dev->cdev);
    
err_unregister:
    unregister_chrdev_region(led_dev->devno,1);
    
err_kfree:
    kfree(led_dev);
    return ret;

}


static void __exit led_exit(void)   
{
    printk("--------^_^ %s------------
",__FUNCTION__);
    device_destroy(led_dev->cls,led_dev->devno);
    class_destroy(led_dev->cls);
    cdev_del(led_dev->cdev);
    unregister_chrdev_region(led_dev->devno,1);
    kfree(led_dev);
}

module_init(led_init);
module_exit(led_exit);
MODULE_LICENSE("GPL");

app.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>


int main(void)
{
    char led [1] = {1};
    
    int fd = open("/dev/led",O_RDWR);
    if(fd < 0){
    perror("open");
    exit(1);
    }

    //闪灯
    int ret = write(fd, led, 1);
    if(ret <0)
    {
        printf("write failed !
");
        exit(0);
    }
    sleep(1);
    
    close(fd);
    return 0;
}

笔记

---

　　配置寄存器和数据寄存器自行查询用户手册（基地址+偏移地址）

　　A64：如下